The desire to integrate data, voice, image and video over high speed digital trunks has led to the development of a packet switching technique called cell relay or asynchronous transfer mode (ATM). ATM traffic is switched and multiplexed in fixed length cells and an ATM network typically provides a number of interconnected nodes which are capable of receiving data from other network nodes and forwarding that data through to other network nodes to its ultimate destination. Nodes are interconnected by transmission paths, each of which supports one or more virtual paths. Each virtual path contains one or more virtual channels. Switching can be performed at the transmission path, virtual path or virtual channel level.
Existing packetized voice formats, such as ITU-T Recommendation G.764 and the Frame Relay Forum's voice over frame relay provide a basic structure for variable bit rate-like voice transport across ATM networks. However, these methods provide no standards for the transport, negotiation of parameters, and/or signaling of legacy telephony using various voice compression techniques. Nor do these methods effectively handle silence compression, signaling or error handling.